From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id C3ECE44894 for ; Sun, 30 Oct 2022 19:14:38 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 41F0368BD23; Sun, 30 Oct 2022 21:14:35 +0200 (EET) Received: from mail-oa1-f54.google.com (mail-oa1-f54.google.com [209.85.160.54]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id C560C68BC41 for ; Sun, 30 Oct 2022 21:14:28 +0200 (EET) Received: by mail-oa1-f54.google.com with SMTP id 586e51a60fabf-13ba86b5ac0so11666966fac.1 for ; Sun, 30 Oct 2022 12:14:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=WTxQTnluKeWBfAKcZKWN0IEQ9JgWJ+IX+VgMCxeoSbM=; b=SnKXlzqhw1feNvB7/xj+VrS0IlqPGfQbYDhRX3W3tRHDRvvm/8FY5uDiFnr81xrzoG lDg5VxHyQQ2JFaqNC6c9jaNJDZU1+no1UagzT98Ca077i4w6e8ffPNrBljv7q39kALNX zKlMUzkqNjVPBVwqm2xFcR4aQ97+QHwiHTWnJVJLTtT2MWJWGu6xQUoHZHQnBRtOvGQw 9Y4/NcgqZFBRw2UlwaqRPrp27ug9mYRv8OELJy+tsVc6iCthnJ+dE9WhM0UGEEetkCmf CgC2KZrRXaCn9CyKbj2/JfJr+bDOyAusjt8vZISkG5SblrTaKDj5x6+kldBbOo6Ql9ig zKbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WTxQTnluKeWBfAKcZKWN0IEQ9JgWJ+IX+VgMCxeoSbM=; b=B7mMTZ66QrSQvIHzWQtYctsPkL/fO047mn4WdTi3EIGj3rf/VPe5RKkiB1pWCw/o7l 96NCmF3GT9sW3YxGVYA/PfxFW3q+/VkbE3uNYSgB98ShH0qzIxizRD0NsX3Z22ELUHSx E5K1TLtihy4HaGTeBN0pOLvm/szFJ0K9etZMzdveK7u/W4bghddhm8kWjYlREVpuECdM 17YsSq8E/Iv9UiMO22nknSb6NiZVExuFJ/d4Ib4qXOMSMOugYGFVBApxtf55XQRzOjHE 6hcZnyD+OHiZrLuLrc5Pc7pjWhdlGkxccIhDcPBMEyih0nKAdGTRAI0BsJZ3Bwg0SsFq OoNA== X-Gm-Message-State: ACrzQf1SVxeLwDMaRVogIfB1gmJxJwsVm2zJULTwHOHL6V0ydtXxe5FS Ht7MHqJsHCaLtLSkgtWJl8PggaprzQA= X-Google-Smtp-Source: AMsMyM6zUJA3Dd8s0G979OKveOM5e0UKJsYH4h2QNMm9tRbXeQmrLzT9SJjFUJT9WHy9taH0jJtAyg== X-Received: by 2002:a05:6870:b38a:b0:130:ea10:79bf with SMTP id w10-20020a056870b38a00b00130ea1079bfmr15349684oap.217.1667157266766; Sun, 30 Oct 2022 12:14:26 -0700 (PDT) Received: from [192.168.0.13] ([191.97.187.183]) by smtp.gmail.com with ESMTPSA id s37-20020a056870632500b0013b09a56d59sm2116300oao.27.2022.10.30.12.14.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 30 Oct 2022 12:14:26 -0700 (PDT) Message-ID: <2a8d16ba-7f6a-720e-f068-d6bfcaf2679b@gmail.com> Date: Sun, 30 Oct 2022 16:14:25 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Content-Language: en-US To: ffmpeg-devel@ffmpeg.org References: <103b6b6c-5c56-2af7-bde6-1e1706d21930@gmail.com> <3a38e8dc-0c3a-eec2-9278-75f2bc6118aa@gmail.com> <01478b24-aae8-ad9c-9947-cefb696ffb39@gmail.com> From: James Almer In-Reply-To: Subject: Re: [FFmpeg-devel] [PATCH] avfilter: add ambisonic decoder filter X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On 10/30/2022 3:58 PM, Paul B Mahol wrote: > On 10/30/22, James Almer wrote: >> On 10/30/2022 3:29 PM, Paul B Mahol wrote: >>> On 10/30/22, James Almer wrote: >>>> >>>> >>>> On 10/30/2022 3:19 PM, Paul B Mahol wrote: >>>>> On 10/30/22, James Almer wrote: >>>>>> On 10/30/2022 12:34 PM, Paul B Mahol wrote: >>>>>>> +static const struct { >>>>>>> + const int order; >>>>>>> + const int inputs; >>>>>>> + const int speakers; >>>>>>> + const int near_field; >>>>>>> + const int type; >>>>>>> + const double xover; >>>>>>> + const AVChannelLayout outlayout; >>>>>>> + const double *speakers_azimuth; >>>>>>> + const double *speakers_elevation; >>>>>>> + const double *speakers_distance; >>>>>>> +} ambisonic_tab[] = { >>>>>>> + [MONO] = { >>>>>>> + .order = 0, >>>>>>> + .inputs = 1, >>>>>>> + .speakers = 1, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO, >>>>>>> + .speakers_azimuth = (const double[1]){ 0. }, >>>>>>> + .speakers_distance = (const double[1]){ 1. }, >>>>>>> + }, >>>>>>> + [STEREO] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 2, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO, >>>>>>> + .speakers_azimuth = (const double[2]){ -30, 30}, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [STEREO_DOWNMIX] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 2, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = >>>>>>> (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO_DOWNMIX, >>>>>>> + .speakers_azimuth = (const double[2]){ -90, 90 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [SURROUND] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 3, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_SURROUND, >>>>>>> + .speakers_azimuth = (const double[3]){ -45, 45, 0 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [L2_1] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 3, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_2_1, >>>>>>> + .speakers_azimuth = (const double[3]){ -45, 45, 180 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [TRIANGLE] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 3, >>>>>>> + .type = 1, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_SURROUND, >>>>>>> + .speakers_azimuth = (const double[3]){ -120, 120, 0 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [QUAD] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 4, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_QUAD, >>>>>>> + .speakers_azimuth = (const double[4]){ -45, 45, -135, 135 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [SQUARE] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 4, >>>>>>> + .type = 1, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_4POINT0, >>>>>>> + .speakers_azimuth = (const double[4]){ 0, -90, 180, 90 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [L4_0] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 4, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_4POINT0, >>>>>>> + .speakers_azimuth = (const double[4]){ -30, 30, 0, 180 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [L5_0] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 5, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = >>>>>>> (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT0_BACK, >>>>>>> + .speakers_azimuth = (const double[5]){ -30, 30, 0, -145, 145 >>>>>>> }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [L5_0_SIDE] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 5, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT0, >>>>>>> + .speakers_azimuth = (const double[5]){ -30, 30, 0, -110, 110 >>>>>>> }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [L6_0] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 6, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_6POINT0, >>>>>>> + .speakers_azimuth = (const double[6]){ -30, 30, 0, 180, >>>>>>> -110, >>>>>>> 110 >>>>>>> }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [L7_0] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 7, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_7POINT0, >>>>>>> + .speakers_azimuth = (const double[7]){ -30, 30, 0, -145, >>>>>>> 145, >>>>>>> -110, 110 }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [TETRA] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 4, >>>>>>> + .type = 2, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_QUAD, >>>>>>> + .speakers_azimuth = (const double[4]){ -90, 90, 0, 180 }, >>>>>>> + .speakers_elevation = (const double[4]){ -35.3, -35.3, 35.3, >>>>>>> 35.3 >>>>>>> }, >>>>>>> + .speakers_distance = same_distance, >>>>>>> + }, >>>>>>> + [CUBE] = { >>>>>>> + .order = 1, >>>>>>> + .inputs = 4, >>>>>>> + .speakers = 8, >>>>>>> + .type = 2, >>>>>>> + .near_field = NF_NONE, >>>>>>> + .xover = 0., >>>>>>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_7POINT1, >>>>>> >>>>>> 7.1 defines an LFE channel, which is clearly not intended here, so it >>>>>> should be either: >>>>>> >>>>>> .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MASK(8, >>>>>> AV_CH_LAYOUT_QUAD | >>>>>> AV_CH_TOP_FRONT_LEFT | >>>>>> AV_CH_TOP_FRONT_RIGHT | >>>>>> AV_CH_TOP_BACK_LEFT | >>>>>> AV_CH_TOP_BACK_RIGHT), >>>>>> >>>>>> Or the AV_CHANNEL_LAYOUT_CUBE layout (using the exact same bitmask as >>>>>> above) after the patch i sent just now is committed. >>>>> >>>>> CUBE is as real cube in 3d space. No current layout in API can be >>>>> described correctly. >>>> >>>> the TOP_* channels are in a different height layer than the other >>>> channels, namely above them. The result for this bitmask is a 3D cube >>>> layout (Left and right speakers both front and back, in two different >>>> height layers). >>> >>> https://en.wikipedia.org/wiki/Ambisonic_reproduction_systems#Cube >> >> "If all speakers are placed in room corners", So a 7.1 layout, besides >> defining one channel as LFE, is also not ideal given that it defines two >> speaker positions in places other than the room corners, and by no means >> describes a 3D cube since all speakers are at the same height. >> The TOP channel ids let you assign four channels to speakers placed in >> the top room corners. > > 7.1 is there just because it have 8 channels. No other reasons. If you want to just say "there are eight channels", then make the AVChannelLayout define 8 channels of order UNSPEC. Let the user then figure out what to do with them. But if you want to actually give each channel a position, then you need to use the proper IDs to describe the intended layout. Using 7.1 here is lying to the user, as it's telling them he needs to place two speakers at the front, two at the back, two to the sides, and all at the same height, plus one channel wrongly feeding the sub woofer. Not to mention what would happen if you try to downmix the stream. swr would just generate awful results. Meanwhile, using cube you'll tell the user to place one speaker on every corner in the room, or a downmixer how to properly handle the channels to get good results (e.g. on headphones). _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".